Lerne Haastrup and Takesha Thomas, son Isaiah suffered brain damage at birth, are involved in a High Court battle with King’s College Hospital.
Photograph: Teri Pengilley for the Guardian

The parents of a brain-damaged baby will ask the high court on Monday to allow an independent expert to assess their son’s likely quality of life, refusing to accept the advice of his doctors that his ventilator should be switched off.

Isaiah Haastrup is eight months old, cannot breathe for himself and has cerebral palsy following a disastrous birth at King’s College hospital. The trust accepts that the delay in obtaining a caesarean for his mother, Tasheka Thomas, contributed to his brain damage.

But, like the parents of Charlie Gard, who fought the termination of life support for their baby through the courts, Isaiah’s parents want further treatment for their son, believing he may one day be well enough to go home.

Lanre Haastrup, Isaiah’s father who is a lawyer practising in Catford, east London, thinks his son may learn to breathe for himself if the drugs he is on are reduced. The doctors say Isaiah needs drugs for issues such as epilepsy associated with his cerebral palsy and to relax his muscles.

“We don’t know what he can do. That is the uncertainty,” he told the Guardian. “We can’t agree for my son to be placed in palliative care to die.

“I don’t want my son to suffer. If he can’t live and is going to die, let him go,” he said. But he does not believe the doctors’ verdict. In cerebral palsy, the symptoms can change, he argues.

“You can say he will not be able to walk straight. I can accept that. It is not unreasonable to say he may be in a wheelchair for the rest of his life. But that is not to say he will not know who we are. It is not to say he will not experience pain or pleasure,” he said.

They accepted what the consultants were telling them about Isaiah’s brain damage for the first few weeks, he said. They were told that he would never move or open his eyes and advised that it would be best to put him into palliative care.

Haastrup and his partner talked it over. “I said these people are the experts. They have spoken. Let’s just accept that Isaiah is not going to make it. There is no point leaving him there [in intensive care]. We were planning to come to terms with that view.

“Then suddenly there was the watershed. The boy opened his eyes. He was turning his head towards our voices.”

The trust said it would not be appropriate to comment on the specifics of Isaiah’s condition before the court hearing.

As with Charlie Gard, the case illustrates the difficulties for doctors and parents when the relationship of trust and confidence breaks down. Haastrup and his partner who visit their baby every day hold the hospital responsible for their son’s condition and have lost all faith in the medical staff.

The trust, however, says that it believes it is acting in the baby’s best interests. “Following a rare and life-threatening obstetric emergency during his mother’s labour, Isaiah suffered an irreversible and profound brain injury,” it said in a statement. “Sadly, despite ongoing intensive treatment and the highest standards of care, he remains severely disabled and fully dependent on life support. Since his birth, there have been no indications that his condition has improved.

“Our priority is his care, comfort and quality of life. Based on his prognosis, we believe that palliative care would be in Isaiah’s best interests. We have sought a number of external expert opinions who agree with our clinical findings.

“Everyone at the trust understands how incredibly distressing this continues to be for his parents. We will continue to involve them in decisions around his care and offer them our support.”

Haastrup draws a parallel with the Gard case, but claims there are differences because Charlie was born with a rare congenital disease, whereas Isaiah was damaged at birth. “He [Charlie] was a lovely boy with very dignified parents. They had a child and the child had an inherent medical issue. They [Great Ormond Street hospital] did all the tests to see what Charlie could do and what options were available and what the future was for Charlie,” he said.

The parents do not accept the expert opinions from King’s and other hospitals that Isaiah’s condition is irremediable and want to hear from somebody outside the NHS. “I want someone who is not connected with the NHS. We are going to get an expert, hopefully with a court order,” said Haastrup.

Their feelings are undoubtedly influenced by the traumatic birth, during which Takesha nearly died. Her uterus ruptured and she lost half her blood. “I was there when my son was born and I saw the whole thing unfold,” said Haastrup, wiping his eyes. “The [baby’s] heart rate was extremely low and yet they ignored all that for 40 minutes. ”

The hospital trust admits there was a delay in obtaining a caesarean – their investigation found that if it had taken place 10 minutes earlier, the brain damage would not have been so severe – but it says the main reason for Isaiah’s condition was a rare event during the labour.

“We conducted a full investigation after his birth that concluded his mother experienced a rare and catastrophic event during labour which was the primary reason for his brain injury. The investigation recognised that specific issues in monitoring during labour were a contributing factor to his condition. We apologise unreservedly for this,” it said.

• This article was amended on 10 November 2017. An earlier version misspelled Lanre Haastrup’s first name as Lerne.